Control apparatus



L. w. CHUBB CONTROL APPARATUS Marqh 18, 1924.

Original Filed June'9, 1919 My/on 660M INVENTOR ATTORNEY IIIIIIIII 11/ III 111 II IIIIIIIIIIIII II Lew/I9 Warr WITNESSES: #490 Patented Mar. 18, 1924.

UNITED STATES. PATENT OFFICE.

LEWIS wAmuNeTo cHUBB, or nnenwoon P RK, PENNSYLVANIA, AssreNon To WESTINGHOUSE ELECTRIC & MANUFACTURING. COMPANY, A CORPORATION or PENNSYLVANIA.

CONTROL APPARATUS.

Original application filed June 9, 1919, Serial No. 302,793. Divided and this application filed September To all whom it may concern:

Be it known that I, LEWIS WARRINGTON CHUBB, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Apparatus, of which the following is a specification, this application being a division of my application Serial No. 302,793, filed June 9, 1919.

My invention relates to control apparatus and it has special relation to the variation of resistance in liquid rhcostats.

One object of my invention is to provide a liquid rheostat wherein means are provided for actively utilizing a relatively large proportion of the electrode surfaces under high-voltage conditions of the rheostat, whereby arcing in the rheostat, when an induction motor or other device to be gov erned is started into operation, is avoided.

Another object of my invention is to provide a moving column of electrolyte between the electrodes, together with means for varying the length or cross-section of said column to change the resistance of the rheostat.

Other more specific objects of my invention will become evident from the following detailed description, taken in conjunctionwith the accompanying drawings, wherein- Figure 1 is a diagrammatic view, partly in side elevation and partly in section, of a liquid rheostat designed in accordance with my invention; and

Fig. 2 is a cross-sectional view of a modified form of liquid rheostat for accomplishin similar results.

eferring to Fig. 1 of the drawing, the apparatus that is illustrated comprises a suitable tank or reservoir 40 having a discharge opening 41 with which suitable pumping apparatus is associated to supply a continuous flow of electrolyte through the manifold or spreader 33. A description of pumping apparatus suitable for this type of liquid rheostat is set forth in the above identified parent application filed June 9, 1919, Serial No. 302, 93.

A plurality of pairs of plates or electrodes 42 are suitably located in the rheostat, and alternate pairs are electrically connected to the conductors 14a and 26a, respectively. Curtains or pieces of cloth 43 and 44, such Serial No. 503,912.

as canvas, are attached to the lower ends of the plates comprising the respective pairs. Consequently, the column of liquid between the plates 42 is carried downwardly to the bottom of the tank, as indicated by the solid arrows, between the curtains 43 and 44, which thus guide the column of liquid. To ensure that the plate area is maintained at the full active value, or, in other words, that the entire inner surfaces of the plates 42 are at all times utilized, the curtains 43 and 44 are caused to approach each other, a certain distance below the edges of the plates 42, to provide a constricted opening or pocket, which will ensure a complete column of electrolyte above the constricted section and, in particular, between the plates 42.

For the purpose of providing the abovementioned constricted opening or pocket, the illustrated apparatus or any equivalent thereof may be employed. The method shown consists in placing rods 45 of wood or other insulating material along the outside of the curtains 43 and 44 at the plane where it is desired to begin the constriction, and the rods 45 are held in the proper relation to each other by means of rope or wire 46. Furthermore, if desired, similar ropes or wires 47 may be employed to join adjacent pairs of curtains and, if the ends of the ropes or wires are fastened to the tank walls, the complete set of curtains is maintained in the proper position to ensure the flow of substantially steady columns of electrolyte downwardly between the pairs of plates.

The initial path of the electric current is indicated by the dotted arrows in the lefthand half of Fig. 2, namely, from one conductor 26a downwardly between one pair of plates 42 and the corresponding curtains, along the moving stream near the bottom of the tank, and upwardly between the next set of curtains and plates to the other conductor 1402. In this way, a liquid path of initially high resistance is provided in the rheostat.

By raising the level of the electrolyte outside of the respective pairs of plates, by means of a valve for changing the size of the dischargeopening 41, or in any other suitable manner, the outer surfaces of the electrodes are also rendered active. During 

